ABSTRACT
In protein chemistry, the physical characterization of the isolated protein from plant or animal sources mostly employs procedures to determine the apparent molecular weight and charge, size, and shape of the molecule. Food proteins, like their physiological cousins, can be made from subunits, and it is also customary to identify and characterize them. Determination of composition provides an estimation of minimum molecular weight of a protein using protein components, namely, amino acid analysis, end-group analyses, and qualitative analysis for prosthetic groups. Amino acid composition of a protein usually provides a method for its quantitative characterization. Hydrolysis of a protein is carried out in 6 N HCl for varying periods of time (20 min to 24 h) at a temperature of 100°C under vacuum. Identification of the N-terminus amino acids of proteins is often useful for characterizing the structural and functional domains and is important for the isolation of recombinant DNA clones.
